sensorservice: add fusion sensors if all events are supported

- Fusion sensors depend on gyro, mag field, and accelerometer
  events in order to emulate these sensors.  Don't create
  them unless ALL of the real hardware devices required exist.

Change-Id: I1bce167a52c2dfc56a07450f858b01b78c39b7fe
Merge branch 'cm-11.0' of git://github.com/CyanogenMod/android_frameworks_native into cm-11.0